Process of making metallic duplicate phonograph-records.



No. 657,527; Patented Sept. I|,' |900. T. A. EDISUN.

PROCESS 0F MAKING METALLIC DUPLICATE PHONGRAPH RECORDS.

(Application med my 4, 1900.) (No Model.)

Witnesses Inventor L .ZW f. fm w50/2a' MW' M UNITED STATES: i PATENT mcn.

:'iHoMAs AQ Eijrso, or LLEWELLYN PARK, NEW JERSEY.

ifRocEss oF MAKING METALLIC DiJPLlcATE PHoNoeRAPH-Rrco'sns;

sPEeIFIcATIoN forming par; of Letters Patent No. 657,527, dated 'september 11, ieo.

Application filed May 4, 17900. Serial N0. 15,453. (No specimens.)

process records possessing a high intrinsic' value may be copied with absolute accuracy, so as to be preserved indenitely. The process also provides for the making from origif nal records of accurate metallic masters suitable for use in the making of subsequent'duplicates by a mechanical process, as is now practised, and which masters by reason of their metallic character will permit the making of a very much larger number of duplicates by a mechanical process than is now possible. i

In carrying my invention into eect I iirst obtain a suitable metallicmatrix, bas-relief,

or negative copy of an original record. As-

suming the original record to have been formed on a cylindrical blank, this `matrix rwill be in the form of a cylindrical shell with the record in negative or v relief within its bore. I then deposit a different metal upon the surface of the matrix carrying the record in negative or bas-relief until the desired thickness of deposit is securedrafter which I subject the matrix carrying the metal deposited thereon or therein to a treatment by Which the deposited metal will be freed from the matrix, so as to therefore carry upon its surface an absolutely-accurate copyof the original record. I preferto ,make the matrix of copper and to deposit silver upon the surface of the matrix carrying the record,

whereby a silver copy will be secured, andb to dissolve the copper matrix from the silver deposit by treatment with hydrochloric acid or other solvent of copper which does not af` feet silver; but it will be understood 4that other metals may be used which may be subjected to other treatments for the separation of the matrix from the metallic deposited copy.`

In carrying my invention specifically into` effect I may conveniently adoptfthe following procedure, from which the scope and modifications of Which my invention is susceptible will be apparent, re ference being had to the accompanying drawings, which are illustrative of the process, and wherein- .'Figure 1 represents a longitudinal sectional view through an ordinary cylindrical phonograph-record, illustrating the deposition of a matrix thereon; Fig. 2, a corresponding View showing the matrix separated from the record, coated on its exterior With a Waterproof material and With a metallic deposit on its bore; and Fig. 3, a corresponding view showing the finished copy or duplicate. r

In all ofthe above Views corresponding parts are represented by the same numerals of reference.

l'represents an ordinary cylindrical phonograph-record made of a soap or soap-like composition, as is common, ha'vinga tapered bore, the record being formed on its exterior face in a spiral groove. Assuming that a record of this character is to be copied in metal, I yfirst secure a matrix 2 of the record. Preferably this matrix is formed by first coating the original record With a minutely-thin film of metal by a process of vacuous deposit, as I describe in my Patent No. 526,147, dated Sepfy tember 18, 1894, after which the film so secured is plated, preferably with copper, by an electrodeposition prop ess until a matrix having a thickness of'about one thirty-second of an inch is secured. 'Ihe matrix obviously may be made by other processes; but that indicated is advantageous, because of its great accuracy. The record 1 is now removed from the matrix 2 either by melting out the cylinder or by subjecting it to cold, so as to sh rink it from the matrix, or in any other way. Obviously I will now have secured a thin cylindrical matrix carrying on its bore a copy in negative or relief of the record4 originally formed in intaglio on the 4cylinder l. This matrix is coated on its exterior and upper and bottom faces with a suitable'waterproof composition-such as stearin, paraffin, o`r other water-repellent substance-said coating being indicated in Fig. 2 by the numeral 3, and af-` ter being s0 prepared the Waterproofed matrix is suspended in a plating-bath and a coating r 4 of a different metal from `the matrix is de" IOC Y talliccopy of acylindrical phonographic rec- 'subjecting the matrix and its silver deposit to the action of hydrochloric acid to dissolve the copper, substantially as set fqrth.

13. The improved process of making a metallic copy of a cylindrical phonographic record, which consists in depositing copper upon the original record to form a cylindrical matrlx, 1n depositing silver upon the bore of the cylindrical matrix, and in subjecting the matrix and silver deposit to hydrochloric acid to dissolve the copper from the silver, substantially as set forth.

14. The improved process of making a me- 

